Industrial truck



y 1937. c. E. COCHRAN INDUSTRIAL TRUCK Filed April 17, 1936 2Sheets-Sheet 1 INVENTOR.

Patented May 11, 1937 "UNITED STATES PATENT OFFICE INDUSTRIAL TRUCKApplication April 17,

2 Claims.

This invention relates to an industrial truck of the tier-lift type. Thegeneral object of the invention is to provide an individual industrialtier-lift truck, of high lift capacity which will be 5 efllcient inoperation, strong and rugged in construction, and capable of beingeconomically manufactured and operated.

A more specific object of the present invention is to provide anindustrial tier-lift truck with a simple arrangement for mounting amovable elevator guide on a fixed elevatorguide in such a manner thatthe tendency for the movable guide to sway or get out of alignmentwiththe fixed guide will be overcome and wherein the reactions 15 on theguide members, due to the load being applied to the movable guide, willbe eifectively overcome, and wherein a minimum amount of power will berequired to raise the movable guide relative to the fixed guide. 4

Other objects of this invention will become more apparent from thefollowing description, relating to the accompanying drawings, whichillustrate a preferred form of the invention. The essential novelcharacteristics of the invention are summarized in the claims.

In the drawings, Fig. 1 is a side elevation of an industrial truck,incorporating an embodiment of the present invention, certain parts ofthe truck being broken away, to more clearly illustrate the internalconstruction thereof; Fig. 2 is a horizontal section, on an enlargedscale, the plane of the section being indicated by the line 2--2 of Fig.1; Fig. 3 is a vertical section, substantially the same as shown in Fig.2, the plane of the section being indicated by the line 3-3 of Fig. 1;Fig. 4 is a fragmentary vertical section, taken along the same line asthat shown in Fig. 3, but illustrating the movable guide in a raisedposition.

The invention has been illustrated in the draw- 40 ings as applied to anindustrial truck of the type described, illustrated and claimed inPatent No.

1,977,815, issued October 23, 1934, to my assignee,

The Elwell-Parker Electric Company.

The general arrangement of such truck, as shown, comprises a relativelyfixed elevated guide A, suitably attached to a truck frame III. Theattached guide supports a movable guide B, and the movable guide, inturn, supports a carriage C, including a suitable load-engaging andlifting means, such as a platform D. or other lifting means is adaptedto be positioned at a comparatively low level for picking up anddepositing loads at such level. The carriage C operates in the movableguide B and is raised and lowered thereon and when the upper limit ofThe platform 1936, Serial No. 74,863

movement of the carriage in the guide B has been reached, theload-engaging means may then be raised further by extending the movableguide 3 with reference to the attached guides. The raising and loweringof the load is accomplished 5 by suitable power hoists E which may beelectrically driven, as shown, or operated by a suitable internalcombustion motor, either of which may be variedly positioned withreference to the frame of the truck. Such hoists operate through 10 aspecial cable and sheave arrangement, as set forth in the patentheretofore mentioned, to raise and lower the platform relative to themovable guide and the movable guide relative to the fixed guide in apredetermined order.

Referring now to Fig. 1, the truck comprises a main chassis or frame I0,having a low slung forward extension l2 and an upright battery, or powerunit housing l3. Suitable traction wheels i4 disposed beneath thebattery housing support the frame, these wheels being'dirigible ornon-dirigible, as desired. The wheels are arranged to be driven by asuitable motor through the usual reduction gearing. The motor isindicated at l5, and is adapted to be controlled by an operator whostands on a rearwardly extending platform I6. The low-slungframeextension i2 is supported by a set of wheels. l'l, preferablydirigibly arranged, and adapted by suitable mechanism, not shown, to becontrolled by the operator through a steering arm, or equivalent device,shown above the platform l6 at l8.

The load-engaging platform may be of any convenient type, and isgenerally indicated at D. The platform is supported by the carriage C,which, as shown, has forwardly extending arms 2| to which the platformis secured. The carriage is also provided with vertically extending arms22, having guiding rollers 23 and 24 which engage suitable guiding meanson the movable elevator guide B. The movable guide B comprises a pair ofinwardly facing structural channels 25, with hearing strips 26 mountedbetween their flanges and on which the rollers 23 are adapted to bear.The rollers 24 of the carriage bear directly against the outer surfacesof the forward flanges of the channels 25. The channels 25 are tiedtogether at their tops by a suitable cap member 21, which serves tomaintain them in spacedapart relation. Other similar spacing members maybe supplied if desired adjacent the bottom of the channel.

The attached elevated guide A, in which the movable guide B istelescopically arranged, comprises, as shown, a pair of inwardly facingstructo the main frame l in any well-known man-' tural channels 30.These channels 30 are secured ner. The rearmost flanges of the channels30 are each provided with a bearing strip 3 I, against v 'frame member33, which serve to brace and maintain the channels spaced apart. Alsoadjacent the upper end of each of these channels 30 is a roller 31,which is rotatably mounted on a suitable stud 38, secured, as bywelding, to the web of its respective channels 30 of the fixed guidemember. These rollers 31 are adapted to bear against guide strips 39,secured to the outer faces of the webs of respective channels 25 of themovable guide 13.

The arrangement of the rollers 32 and 31, above described, has manyadvantages in industrial trucks of this type, and especially in thosetrucks having a hoisting mechanism arranged to raise and lower theload-engaging member in the movable guideway to its maximum height;before the movable guideway is raised or lowered relative to the fixedguide.

Under ordinary operating conditions, and especially duringtransportation of a load, the load must be raised a distance suflicientto clear the floor or truck-supporting surface. At the same time it isimportant that the overall height of the truck be maintained at aminimum, during its transportation from place to place. Obviously, toaccomplish this, the movable guide must remain in its lowered positionduring such transportation, while the carriage must be raised relativeto the movable guide.

One type of hoisting mechanism, for accomplishing the purpose above setforth, is shown, described and claimed in the patent heretoforementioned. Briefly, such mechanism comprises an electric motor 40,arranged through the medium of suitable reduction gearing, (not shown)to drive a pair of winding drums 4|. These drums are mounted on the mainframe adjacent its lower end of the elevator structure. A continuousstrand of cable, the opposite ends of which are tied to respectivewinding drums 4|, is used to raise and lower the carriage and movableguide. This cable passes from each drum. Such stretches of the cable areshown in Fig. 3, at 42. These cable stretches extend upwardly torespective sheaves 43, mounted on the fixed guide A in a well-knownmanner. From the sheaves 43, the respective cable stretches passdownwardly, as indicated at 44, to a second pair of sheaves 45, carriedadjacent the lower 'ends of the respective channel members 25 of ber 53.secured to the movable guide B adjacent its upper end. a

The above described arrangement of cable mechanism is such that duringthe initial application of the load, the winding and cable mechanismwill operate with twice the mechanical advantage to raise the platform,as it does to raise the elevated guide B. Hence, the platform will beraised to the limit of its movement before the elevating guide beginsits movement. Such a cablemechanism is described more in detail in thepatent above referred to, and reference to such patent may be had for amore detailed description of its operation.

Heretofore, different types of mountings between the elevatable guideand the stationary guide have been used with more or less success. Incertain instances, the channel members of the guide B have been arrangedin slidingcon tact, throughout their length, with the channel members ofthe stationary guide A. However, it has been found difficult to maintainsuch guideways clean and free from dirt. Hence, when such slidingcontact is utilized, the power demands are such that the hoist motorsand their power supply, such as electric batteries, require considerablevehicle platform or housing space. This, of course, creates a truckhaving a comparatively long frame and wheel base, making such truckdiflicult to operate in the narrow, sharp-cornered aisleways of ordinaryindustrial establishments.

I have maintained the power requirements at a minimum by interposing theanti-friction rollers 32 and 31 between the movable guide and thestationary guide. Arrangements, however, have been provided, such asshown in the patent heretofore mentioned, which utilize anti-frictionrollers.

In the past, when rollers have been used, it has been customary tosecure two pairs of rollers to the movable guide, adjacent its lowerends. Such construction is shown in the prior patent, heretoforementioned, and has certain advantages over merely sliding one channel inanother. Nevertheless, this construction also required considerablepower to raise the movable guide in the stationary guide, and thereforethe attendant disadvantages.

By arranging mounting of one pair of rollers (32) on the movable guideadjacent the bottom thereof, and mounting another pair of rollers (31)on the fixed guide adjacent the top thereof, I have added greatly to therigidity and strength of the structure, as I prevent swaying of the loadand movable elevator guide during the transportation of the load fromplace to place. I also surprisingly decrease the amount of powerrequired to raise the movable guide. Under normal conditions, that is,when the movable guide is in its lowermost position, the movable guideis supported adjacent its upper and lower ends, preventing undue bindingof the rollers in the guides.

I find that this improved arrangement of the guides permits the movableguide members to be raised higher in the stationary guide than ispossible where both pairs of rollers are carried by the movable guideadjacent its lower end. In the latter instance, the rollers must bespaced apart it is possible, when the truck is being used forcomparatively light loads, to raise the movable guide memberconsiderably higher than when a maximum load is being raised andlowered. My arrangement of the rollers is such that I may readily raisethem into contact with each other if the weight of the load permits. Toprevent damage to the mechanism, the usual adjustable stop mechanism forcontrolling the maximum raising and lowering of the movable elevator ispreferably supplied. Such a mechanism, however, is not illustrated, butreference to the above patent heretofore referred to, may be had, for afull and complete description thereof. Suifice it here to say that themechanism is readily adjusted to limit the maximum height that themovable guide may be raised by stopping the hoist motor upon reachingsuch limit. The adjustment is arranged so that it may be manuallychanged to accommodate either a light or heavy weight load.

From the foregoing description, it will be seen that I have provided anelevating platform truck of the tier-lift type, which is rigid inconstruction, requires a minimum amount of power, and wherein themovable guide can be raised together with the load a maximum distanceconsistent with the weight of the load being handled.

I claim:

1. In an industrial tier-lift truck, a main frame, an elongated uprightelevator guide comprising a pair of inwardly facing channel membersfixed against vertical movement relative to the main frame, an elongatedupright guideway carried by eachof said channel members, an elongatedupright movable guide comprising a second pair of inwardly facingchannel members,a guideway carried by each of said second-named channelmembers, a roller rotatably mounted on each channel member of the fixedguide adjacent its upper end and adapted to bear against the respectiveguideways oi the movable guide channels, a roller mounted on each of themovable guide channels adjacent their lowermost ends respectively, saidlast-named rollers being arranged and adapted to coact with therespective guideways of the fixed guide channels, a load-engagingelevator member mounted for vertical movement on said movable guide, andpower-operated means to raise the load elevator engaging member relativeto the movable guide and the movable guide to the fixed guide.

2. In an industrial tier-lift truck, a main frame, an elongated uprightelevator guide comprising a pair of inwardly facing channel membersfixed to the main frame, an elongated upright guideway carried by eachof said channel members, an elongated upright movable guide comprisingguideways carried by said movable guide and extending into the regionbetween the flanges of the respective channels, a roller rotatablymounted on each channel member of the fixed guide adjacent its upper endand adapted to bear against the respective guideways of the movableguide, a pair of rollers carried by the movable guide adjacent itslowermost end, and adapted to bear against respective guideways of thefixed guide, a load-engaging elevator member mounted for verticalmovement on said movable guide, and means to raise first the loadelevator engaging member relative to the movable guide and subsequentlyto raise the movable guide and load-engaging member as a unit relativeto the fixed guide.

CLYDE E. COCHRAN.

